Applicant is the owner of U.S. Pat. No. 3,757,729 issued Sept. 11, 1973. While the device of this patent has worked phenomenally well, it does have limitations which have triggered changes required and perhaps necessary for a fully useful mechanism. For example, in the use of the sculling mechanism of the issued Patent, it has been found that a reverse was necessary in many instances.
Also, it has been found that a more desirable and smoother sculling result could be accomplished with much less effort and therefore quieter, by providing windows in the horizontally connected blades to lessen the drag on the return or non-power stroke, without impairing in any way resistance provided by the blades in the power stroke.